Means for reducing skin-friction of ships.



No. 654,655. Patented July 3|, I900. E. LINDEMANN. MEANS FOR REDUCING SKIN FRICTION 0F SHIPS.

(Application filed Sept 5, 1899.)

(No Model.)

17' f 11 If I11 11111111 17/ //1// Witnesses;

J71 vento? M920 QM? NITED STATES T EPA-TENT -rFrcE-i.

EDUARD LINDEMANN, or MUNICH, GERMANY.

MEANS FOR.REDUCING SKlN-FRICTION OF SHIPS.

SPECIFICATION forming part of Letters Patent imese gess, dated July 31, 1900.

Application filedSeptemlae'r To all whom it 12mg, concern..- 7

Be it known that I, EDUARD LINDEMANN, engineer, a citizen of Germany, residing at Munich, Bavaria, Germany, (post-office address, Schellingstrasse 41 have invented a certain new and useful Improvement in Re ducing Friction of Ships Sides; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

By the movement ofships through the water an essential resistance is caused by the friction, which hinders the fast movement of the same, and the result is a diminution of speed caused by the friction of the ships bow with the water. The greater the speed the greater will be the resistance. By the diminution of the friction-surface between the exterior of the ship and the water the friction and resistance would be lessened. The following method and the hereinafter-described arrangement are such that the amount of friction is lessened by providing between the outside of the vessel and the Water a thin layer of air. As the skin of fishes is provided with scales, the slippery nature of the slime of the same lessens the friction between the fish and the water. In a like manner if the ships bow were covered with metal plates having spaces between the friction between the ships bow and the water would be lessened by air escaping therefrom. For this purpose so much of the surface of the ship as lies under water is surrounded with a thin air layer in a similar manner as theskin of fishes is covered with slime. This air layer is automatically formed by the speed of movement of the ship without mechanical means or compressed'air. The scale-like metal plates'lying one upon the other form pockets over which by the movement of the ship the water glides, so as to draw air out of the pockets. This produces an exterior air layer acting against the friction, lessening the effect of the friction and increasing the speed. The greater the speed in a like manner will the air-space be increased,

proportionally reducing the resistance.

In the annexed drawings,Fig11re 1 is a crosssection of a ship. Fig. 2 isaside view of the same. Fig. 3 is alongitudinal section after the'line a b. Fig. 4 is a longitudinal section .pockets.

5, 1299. SerialNo. 729,526. (No model.)

after the line 0 d. Figs. 5 and 6 show. sectional views of the plates.

In the exterior of the vessel narrow vertical overlapping plates (0 b c (1, Figs. 3, 4, and 5, are arranged, which extend from the edge to the keelof the vessel, Figs.1 and 2. Each plate overlaps the next rear one in a similar manner to the scales of a fish, Fig. 5. Between each of these platesa pocket, as shown in Figs. 5 and 6, is formed,which from its upper part m, Figs. 1 and 2, to the part n is closed and of which the part below b coming underneath the water-line is open. At the keel line Z19, Fig. 2, the pockets are closed. The plates are arrangedso that between each of them is a narrow opening or slit .9, Figs. 1, 2, and 3, under the water-line. The lowerpart a Z, Fig. 1, of these pockets 7o conforms to the out-line of the ship and fits closely thereto; but the upper part m rris separated from the same, so that an air-chamber 70, Figs. 1 and 3, is formed. This airchamber 70, Fig. 3, is open at the bow of the ship and closed at the stern, so that by the forward movement of the ship air is drawn into the air-chamber and passes into all the, pockets. The air-chamber is, Fig. 1, is connected at its lower that the air by reason of the pressure will pass into the pockets, rushing out of the same through their narrow openings. When the ship is stationary, the pockets below the water are filled with water. The water will not remain in the pockets so long as the speed of the ship is greater in proportion to the flow of the Water which is governed by the water-pressure and the draft of the ship. Thus by the action of the moving water air is'drawn' out through the openings of the The suction of the air by the water is assisted by the entrance of the air into the air-chambers open at the bow of the ship. It results, therefore, ward movement of the ship the water in the pockets is forced out through the narrow openings or slits of the same by theair-pres sure in the air-chamber Z0, Fig. 3. The slit openings sof the pockets are connected towe gether at suitable points i r q a: y .2, Fig.1, blocks being interposed.

As the whole surface of the ship is cov ered with the overlapping plates, the whole partto the pockets, so 80 that by the forv surface when moving is incased, asit were, with a layer of air on account of the air passing out of the pockets, such outflow of air being caused by the movement of the ship through the water. The greater the speed of the ship the greater the air-layer. The air layer thus reduces the amount of the frictional surface, and the speed is increased. The action is automatic. In order to further increase the speed, steam can be introduced into the air-chamber, Fig. 3, so that both air and steam can pass into and out of the pockets.

Having now described my invention, I claim the following: 1

1. The combination with a side of a ship, of a series of plates secured transversely thereto, each plate extending rearwardly and contacting at its free edge with the adjacent rear plate, said contacting edges having apertures below the water-line, and means for supplying air to the spaces between the plates, substantially as described.

2. The combination with the side of a ship, of a series of plates secured transversely thereto, each plate extending rearwardly and con= tacting at its free edge with the adjacent rear plate, said contacting edges having apertures below the water-line, and means for supplying air from the bow of the ship to the spaces between the plates,substantially as described.

3. The combination with the side of a ship,

- of a series of plates secured transversely thereto, each plate extending rearwardlyin a curve convex side upwardly, said plates contacting at their free edges with the adjacent rear plates andhaving apertures in proximity to said contacting edges and below the waterline, and means for supplying air to the spaces between the said plates, substantially as described. V

4. The combination with the side of a ship, of a longitudinal partition extending from the side at a short distance below the water-line upwardly, a series of plates secured transversely to said partition and'also to the side of the ship below said partition, each plate extending rearwardly and contacting at its free edge with the adjacent rear plate, said contacting edges having apertures below the Water-line, said partition having apertures communicating with the spaces between said plates, and means for supplying air to the space between the partition and the side of the ship, substantially as described.

5. The combination with the side of a ship, of a longitudinal partition extending from the side at a short distance below the water-line upwardly, a series of plates secured transversely to said partition and also to the side of the ship below said partition, each plate extending rearwardly and contacting at its free edge with the adjacent 'rear plate, said contacting edges having apertures below the water-line, said partition having apertures communicating with the spaces between said plates and also having communication with the atmosphere at the bow of the ship, sub= stantially as described.

6. The combination with the side of a ship, of a longitudinal partition diverging from the side of the ship on a line below the water-line upwardly, a series of plates secured transversely to said partition and also to the side of the ship below said partition, each plate extending rearwardly and contacting at its free edge with the adjacent rear plate, said contacting edges having apertures below the waterline, said partition having apertures communicating with the spaces between said plates, and means for supplying air to the space between the partition and the side of the ship, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

EDUARD LIN DEMANN.

Witnesses: 1

EMIL HENZEL, ANTON REIss. 

